Question

ignoring air resistance, which of the following is the correct free - body diagram: clear all 1 2 4 3

Explanation:

Step1: Identify forces in general

For an object on a surface, there is always gravitational force ($F_{grav}$) acting downwards and a normal force ($F_{norm}$) acting perpendicular to the surface upwards.

Step2: Analyze horizontal forces

If there are horizontal forces, they could be applied forces ($F_{app}$) and frictional forces ($F_{fric}$). In the given diagrams, we need to check if the directions and presence of these forces are consistent with the object's motion or the described scenario. Since no scenario is given, we can't definitively choose a diagram. But in a typical non - accelerating object on a flat surface with no external vertical forces other than gravity and normal, and horizontal forces present, we should have balanced or unbalanced horizontal forces depending on motion and always $F_{grav}$ down and $F_{norm}$ up.

Answer:

(No specific answer can be given as the question asking for the correct free - body diagram is incomplete without context about the object's motion or situation. But if we assume a general horizontal - surface situation with no vertical motion other than gravity and normal force and horizontal forces, we need to analyze based on Newton's laws.)